Table 1.
Study Period (Dates covered) | Oct. 20 – Dec. 20, 2021 |
---|---|
Assumed COVID-19 Epidemiological Characteristics | |
Latent period durationa | 2 days |
Basic reproduction numberb | R0 = 5 |
% cases asymptomaticc | 40% |
Infectiousness of asymptomatic casesd | 75% |
% vaccinated in general populatione | 53.8% |
Vaccine effectivenessf | 88% |
Immunity durationg | 180 days |
Inputs Specific to COVID-19 Mask Mandate | |
Mask effectivenessh | |
Pre-mandate | 3.6% – 16.8% |
Post-mandate | 6.1% – 21.3% |
Inputs Specific to COVID-19 Vaccinate-or-Test Requirement | |
Size of the population affected by requirementi | 929,370 |
% vaccinated in sub-population affected by requirementj | |
Pre-requirement | 64.8% |
Post-requirement | 75.9% |
aPer the literature, we used a two-day latent period associated with the SARS-CoV-2 Delta variant [20, 21]
bPer the literature, we used a basic reproduction number of R0 = 5.0 associated with the SARS-CoV-2 Delta variant [22, 23]. The infectivity distribution varies over time and is spread over an 11-day period [24, 25], and the effective reproduction number further depends on the estimated impact of non-pharmaceutical interventions (NPIs) and the size of the susceptible population, see Technical Appendix for more details
cAsymptomatic COVID-19 cases. Patients can be infected, and become infectious, without being symptomatic. They can and likely do contribute to onward transmission of the pathogen [26]
dInfectiousness of asymptomatic COVID-19 cases relative to symptomatic cases [26]
eBased on CDC COVID-19 vaccination data [27]—these data represent overall coverage among all ages at the beginning of the study period
fCOVID-19 vaccine effectiveness is based on the effectiveness of two doses of the monovalent mRNA BNT162b2 (Pfizer-BioNTech, Comirnaty) against the Delta variant [28]
gWe assume SARS-CoV-2 immunity lasts 180 days on average [29], this includes both vaccine-induced and disease-induced immunity
hMask effectiveness is the product of (i) mask efficacy and (ii) mask compliance. The resultant values are the average mask effectiveness in the state of Illinois, for the time-period studied. See Technical Appendix for more details
iBased on Data from the U.S. Bureau of Labor Statistics [30]. See Appendix Table A2
jBased on data from the Centers for Disease Control and Prevention (CDC)’s National Healthcare Safety Network (NHSN) for CMS-certified nursing homes in IL [31]. Note that this data only represents a sub-population of the total population affected by the vaccinate-or-test requirement. See Appendix Table A3